Claims for Patent: 8,168,209

Summary for Patent: 8,168,209

Title:	Method and composition for administering an NMDA receptor antagonist to a subject
Abstract:	The invention provides methods and compositions for administering an NMDA receptor antagonist (e.g., memantine) to a subject.
Inventor(s):	Went; Gregory T. (Mill Valley, CA), Fultz; Timothy J. (Pleasant Hill, CA), Porter; Seth (San Carlos, CA), Meyerson; Laurence R. (Las Vegas, NV), Burkoth; Timothy S. (San Francisco, CA)
Assignee:	Adamas Pharmaceuticals, Inc. (Emeryville, CA)
Application Number:	12/512,701
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 8,168,209
Patent Claims:	1. A solid pharmaceutical composition in a unit dosage form for once daily oral administration comprising an extended release formulation of 5 to 40 mg memantine or pharmaceutically acceptable salt thereof, wherein administration of a dose of the composition to a human subject provides a plasma memantine concentration profile, as measured in a single-dose human PK study, characterized by a change in memantine concentration as a function of time (dC/dT) that is less than 50% that of an immediate release dosage form comprising the same dose of memantine as the composition, wherein the dC/dT is measured between the time period of 0 to Tmax of the immediate release form of memantine. 2. The composition of claim 1 wherein the concentration profile is further characterized by a memantine Tmax of at least 19 hours. 3. The composition of claim 1 or 2 wherein the concentration profile is further characterized by a maximum memantine plasma concentration to mean memantine plasma concentration ratio (Cmax/Cmean) of about 2.5 to 2 at 1 hour to at least 6 hours after administration. 4. The composition of claim 3 wherein the Cmax/Cmean is about 2.5 to 2 at 1 hour to at least 9 hours after administration. 5. The composition of claim 1, wherein at least 98% of the memantine or pharmaceutically acceptable salt thereof is in an extended release form. 6. The composition of claim 1, wherein the unit dosage form is a capsule and wherein the memantine or pharmaceutically acceptable salt thereof is formulated as pellets. 7. The composition of claim 6, wherein the pellets comprise an extended release coating. 8. The composition of claim 7, wherein the extended release coating comprises an insoluble matrix polymer and a water soluble material. 9. The composition of claim 8, wherein the insoluble matrix polymer comprises ethyl cellulose and the water soluble material comprises polyvinylpyrrolidone. 10. The composition of claim 1 comprising 12.5-40 mg memantine or pharmaceutically acceptable salt thereof. 11. The composition of claim 1 comprising 25-40 mg memantine or pharmaceutically acceptable salt thereof. 12. The composition of claim 1 having a memantine in vitro dissolution profile ranging between 0.1-20% in one hour, 5-30% in two hours, 40-80% in six hours, and 50-90% in 10 hours, wherein the dissolution profile is determined using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37.+-.0.5.degree. C., in 500 ml water. 13. The composition of claim 12 in which the dissolution profile is at least 70% in 10 hours and at least 90% in 12 hours. 14. The composition of claim 1 having a memantine in vitro dissolution profile ranging between 0.1-20% in one hour, 5-30% in two hours, 40-80% in six hours, and 50-90% in 10 hours, wherein the dissolution profile is determined using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37.+-.0.5.degree. C., in an acidic dissolution medium. 15. The composition of claim 1, wherein the extended release formulation of memantine or pharmaceutically acceptable salt thereof comprises ethyl cellulose, polyethylene glycol, hydroxypropylmethyl cellulose and polyvinylpyrrolidone.